This invention relates to a single control proportioning valve for liquids such as hot and cold water, and more particularly to such a proportioning valve which is simplified, economical and improved, and which functions accurately without requiring close tolerances in the component parts.
One object of the invention is to provide a single control proportioning valve which is devoid of a conventional valve body, thereby making possible significant cost savings in manufacture.
Another object is to provide a proportioning valve having a simple support adapted to be mounted on a sink. The valving and proportioning functions are provided by a pair of spaced resilient tubes, and an elongated control cam extending between and in engagement with the tubes to vary the internal cross sectional areas of the tubes, the cam being rotatable and axially movable and having a cylindrical valve-closing length and an eccentric conical valve-opening length.
Another object is to provide in such a proportioning valve a dual bearing means on the support for the cam at opposite end portions of the cam, the dual bearing means being effective to stabilize the cam against disruptive lateral and axial movements which in the absence of the dual bearing means tend to result from pressures exerted on the cam by the resilient tubes due to the pressurized liquids therein.
Still another object is to provide a proportioning valve wherein the proportioned fluids are well mixed despite a comparatively small mixing chamber, thereby reducing a tendence toward objectionable laminar flow.
Another object is to provide such a proportioning valve which utilizes an aerator and yet has an acceptably low noise level.
As far as is known, the closest prior patents are U.S. Pat. No. 3,172,426 and U.S. Pat. No. 3,774,643.
The proportioning valves of the aforesaid patents, while providing functional and cost improvement over predecessor proportioning valves, utilize more or less conventional valve bodies, thereby involving manufacturing costs therefor, and are subject to disruptive lateral and axial movements of the control cam which tend to result from pressures exerted on the cam by the resilient tubes due to the pressurized liquids therein.
Further, prior proportioning valves having comparatively small mixing chambers tend toward laminar flow, and, when aerators are used therewith, tend to produce noise exceeding an acceptably low level.